1. Field of the Invention
The present invention relates to a device and method of managing power, and more particularly, to a device and method for power management in a display device.
2. Discussion of the Related Art
In a conventional display device having a digital cable ready (DCR) function, there are two modes associated power management, namely, stand-by mode and normal mode. In stand-by mode, a minimum amount of power (e.g., amount of power just enough to receive signals from a remote control device) is supplied to the display device. In normal mode, a sufficient amount of power is supplied to the display device enabling a user to normally operate and control the display device.
FIG. 1 is a block diagram illustrating an operation of power management units of a display device in stand-by mode. In FIG. 1 where the display device 1 is in stand-by mode, an alternating current (AC) is supplied to the AC power input unit 2. However, because a switch (SW1) is turned off or open, the AC power follows the path where power is supplied only to a first rectifying unit 3 which is connected to a micro computer power supply unit 4. In the second rectifying unit 5, the AC power supplied to the first rectifying unit 3 is converted AC power to a direct current (DC) power, which is then supplied to the power supply unit 4.
FIG. 2 is a block diagram illustrating an operation of power management units of a display device in normal mode. In FIG. 2 where the display device 1 is in normal mode, the AC power is supplied to the AC power input unit 8. Here, because the switch (SW2) is turned on or closed, the AC power is supplied not only to the first rectifying unit 9 but also to the second rectifying unit 11. The second rectifying unit 11 is connected with a power supply unit for signal processing 13 and a power supply unit for display 14. In addition, the first rectifying unit 9 converts the AC power to the DC power, and then transmits the converted DC current to the micro computer power supply unit 10. Furthermore, the second rectifying unit 11 converts the AC power to the DC power, and then transmits the converted DC current to a power factor correction (PFC) unit 12. The PFC unit 12 thereafter supplies to all the power supply units including the DC power to the power supply unit for signal processing 13 and the power supply unit for display 14. Here, the PFC unit 12 refers to a type of a power-saving circuit added to the power management device in order to improve power efficiency.
The power supply units of the display device have the following problems. First, according to the power management units of the conventional display device only have two modes, namely, stand-by mode and normal mode, a user cannot turn on or operate the display module unless in normal mode. In addition, the problem of normal mode is that power is supplied to the display module unnecessarily even if the user does not wish to view the display or to have power provided to the display module.
In addition, even when only minimum amount of power is supplied to the power management units, power is passed through the PFC unit, resulting in inefficient power management.